Functional neuroimaging has become a widely used approach for studying substance use and addiction. This is particularly true in the area of research on cigarette smoking, which remains one of the largest threats to public health in the world. Neuroimaging research on the use of cigarettes and other substances has focused largely on characterizing brain activity associated with drug craving (an intense urge or desire to use drugs). This reflects the prevailing view that craving plays a central role in the maintenance of addiction and serves as a major barrier to treatment and recovery. Over the past several years, researchers using neuroimaging to study craving have benefitted from a number of significant methodological advances (e.g., increasingly sophisticated data analysis methods). However, the methods that are used for subjective affective experience have changed very little, and investigators must largely rely upon the same self-report measures that have been available since the earliest days of neuroimaging craving research. Used in isolation, self-report measures typically lack the sensitivity and precision that are needed to relate momentary affective experience to craving-related brain activity ? an important limitation given the intimate relationship between craving and affect. The goal of the proposed research is to address this barrier to progress in the field by developing a novel method for measuring subjective affective experience in neuroimaging craving research that harnesses the unique strengths of facial expression analysis. Specifically, this method entails recording participants' facial expressions using a magnetic resonance imaging (MRI) compatible camera and then using facial coding analysis to derive a time course of affective reactions from the videos. By providing a way to unobtrusively capture moment-to-moment changes in affect, facial coding is an ideal method for connecting fluid affective reactions to dynamic changes in brain activity in the context of craving. The proposed strategy of integrating the assessment of facial expressions of affect with neuroimaging methods will be tested in a sample of adult daily smokers. Facial expressions will be recorded as participants complete a functional MRI (fMRI) protocol that has proven to be highly effective for provoking strong cigarette cravings. The specific aims of the project are: 1) To demonstrate the feasibility of measuring affect by analyzing video recordings of facial expressions displayed during fMRI; and 2) To demonstrate that moment-to-moment changes in affect are meaningfully associated with ongoing brain activity under conditions designed to produce robust craving. If successful, the proposed project will provide a foundation for using this new method to explore a variety of questions that are currently very difficult to address (e.g., characterizing how affect changes dynamically in relation to brain activity when smokers attempt to regulate their craving). Accordingly, this comprehensive and multimodal approach to assessment has the potential to make a major impact by providing new insights into the links between brain activity and affect in the domain of drug addiction and in many other areas, more broadly.